Camera, computer program and method for measuring thermal radiation and thermal rates of change

ABSTRACT

A camera, computer program, and method for determining and displaying temperature rates of change for regions within the camera&#39;s field of view. More specifically, the embodiments provide for the continuous, real-time temperature measurement and display of a plurality of objects within the camera&#39;s field of view, and further for the real-time processing and display of the temperature rates of change for the region.

RELATED APPLICATIONS

This non-provisional patent application is a continuation applicationand claims priority benefit, with regard to all common subject matter,of commonly assigned U.S. patent application Ser. No. 14/677,192, filedApr. 2, 2015, and entitled “CAMERA, COMPUTER PROGRAM AND METHOD FORMEASURING THERMAL RADIATION AND THERMAL RATES OF CHANGE,” which is nowU.S. Pat. No. 9,372,120, issued Jun. 21, 2016 (“the '120 patent”). The'120 patent is a continuation application and claims priority benefit,with regard to all common subject matter, of commonly assigned U.S.patent application Ser. No. 13/594,341, filed Aug. 24, 2012, andentitled “CAMERA, COMPUTER PROGRAM AND METHOD FOR MEASURING THERMALRADIATION AND THERMAL RATES OF CHANGE,” which is now U.S. Pat. No.9,000,371, issued Apr. 7, 2015 (“the '371 patent”). The '371 patent is anon-provisional application that claims priority benefit, with regard toall common subject matter, of earlier-filed U.S. Provisional PatentApplication No. 61/527,724, filed Aug. 26, 2011, and entitled “THERMALCURRENT DETECTION APPARATUS AND METHOD.” The identified earlier-filedpatents and provisional patent application are hereby incorporated byreference in their entirety into the present application.

BACKGROUND

1. Field

Embodiments of the present invention are directed to the technical fieldof imaging cameras and image processing. More particularly, theembodiments are directed to a thermal and infrared imaging camera,computer program, and method for displaying visual representations ofthermal scenes and for determining and displaying temperature rates ofchange for objects within the scenes.

2. Related Art

Thermal imaging systems, such as thermal cameras, are often employed intemperature and/or heat measurement applications. Objects with atemperature above absolute zero emit heat in the form of thermalradiation. The intensity of the emitted radiation increases as thetemperature of the objects increase. Thus, the temperature of objectscan be determined by measuring the intensity of the radiation theobjects emit. Typical thermal cameras measure thermal radiation bysensing radiation in the infrared range. The cameras convert theintensity of the sensed infrared radiation (IR) into electrical signals.The electrical signals are, thus, representative of the IR intensityemitted from objects within the camera's field of view. The signals canthen be processed and converted to a two-dimensional visualrepresentation of the IR intensity of the scene. Such a representationfacilitates the creation of a coherent visible picture.

Standard thermal imaging cameras may provide a user with feedback suchas maximum and minimum scene temperatures. The cameras may also convertthe sensed IR into a visual display, while providing color palettegradients representative of all temperatures within a given scene. Thesecameras work well for static temperature readings in which the userwishes to see the temperature maximums and minimums out of a span oftemperatures within a given spatial area or scene. Applications for suchcameras generally involve diagnostic analysis in which a maximum statictemperature or distribution of temperatures is needed. A typicalapplication is found in the home inspection market, wherein thermalimaging cameras may be used to locate heat losses, insulation anomalies,leaks, or other structural issues.

However, standard thermal imaging cameras often have at least someinaccuracies in the detected IR and displayed visual representation,which is due to reflected energy and the differing emissivities forobjects within the camera's field of view. In addition, in someapplications it is desirable to obtain more information regarding theparticular objects being imaged, such as a time and/or a spatial rate ofchange of emitted IR and temperatures for the objects.

SUMMARY

Embodiments provide for a camera, computer program, and method fordetermining temperature rates of change for objects within the camera'sfield of view. More specifically, the embodiments provide for thecontinuous, real-time temperature measurement and display of a pluralityof objects within the camera's field of view, and further for thereal-time processing and display of the temperature rates of change forsaid objects.

Embodiments of the present invention include a thermal imaging cameracomprising a camera housing; an optical assembly that directs IRradiation into the camera housing; an IR sensor positioned within thehousing that includes a plurality of sensing elements that senses IRradiation; a memory element positioned within the housing and operableto stores digital information; a processing element positioned withinthe housing and operable to manipulate the digital information; anelectronic display for displaying visual images and/or videos; and auser interface for receiving a user's input and transmitting the inputto the camera. The camera senses IR radiation emitted from objectswithin the camera's field of view and further to converts the sensedradiation into a visual representation of the radiation. In embodiments,the sensor's plurality of sensing elements emits electrical signalsbased on the intensity of IR radiation incident upon the plurality ofsensing elements. The camera's processing element then converts theelectrical signals into a two-dimensional visual representation of theIR radiation, which may be displayed for viewing by the camera's user.As every sensing element of the sensor may correspond to a pixel of thedisplay device, the display device may display a visual representationof the IR radiation within the camera's field of view. The cameracontinually senses the IR radiation at a given frequency rate, hereinreferred to as a “frame rate.” The IR captured for each frame rate maybe hereinafter referred to as a “thermal scene.” Because the camerasenses and displays the thermal scene on a near-continuous basis, thevisual display may be in the form of a video display. In furtherembodiments, the processing element may manipulate the electricalsignals emitted from the sensor to provide increased accuracy andprecision of the visual representations of the thermal scene. Inaddition, the processing element may manipulate the electrical signalsto provide other useful information to the user, such as the temperatureof each object within the thermal scene, or the minimum, maximum, andaverage temperatures of the scene. In even further embodiments, theprocessing element may also determine and provide temperature rates ofchange of objects within the camera's field of view. Such temperaturerates of change may either be time based rates of change or spatialbased rates of change. It is understood that memory and processingelements are controlled and directed by the computer program of thepresent invention.

Additional embodiments of the present invention include methods formeasuring the temperature rates of change for objects within thecamera's field of view. An exemplary method includes the initial step ofobtaining temperature data from objects within the camera's field ofview. Because the camera may function as a nearly-continuous real-timevideo camera, the camera obtains temperature measurements for eachthermal scene. Next, areas of interest within the scene are detected andsaved in the memory element. For subsequent scenes, additional sets oftemperature data from objects within the field of view are obtained.Areas of interest within the subsequent scenes may also be detected andsaved. After data has been obtained from at least two scenes, the methodincludes the step of attempting to match the areas of interest from themost recent scene with those obtained from a previous scene. If an areaof interest is matched, then the difference between the temperatures ofthe matched areas of interest is calculated to determine a temperaturerate of change. Because the camera operates to generate visualrepresentations of the temperature data on a nearly-continuous real-timevideo basis, the areas of interest may be referenced against each other,while in a plurality of orientations, such that even matching areas ofinterest that change orientations or positions from scene to scene maybe recognized and the temperature differences may be calculated.

Additional embodiments of the present invention may provide for areas ofinterest within the camera's field of view to be detected and tracked.In such an embodiment, the camera may be attached to one or moreservo-motors that operate to rotate the camera about one or morerotational axes. As areas of interest are detected, the locations of thearea of interest may be calculated, and the camera operates to commandthe servo-motors to direct the camera in such a position that the areaof interest is positioned within the center of the camera's field ofview. As the area of interest moves, the displacement is calculated andthe servo-motors are again commanded to direct the camera into acentering position. Even further embodiments may include thedetermination of likely positions for the area of interest to be in thefuture. Such capabilities permit the servo-motors to prepare to directthe camera before the areas of interest have actually changed positions.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the present invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 is a front perspective view of the thermal imaging camera ofembodiments of the present invention;

FIG. 2 is a rear perspective view of the thermal imaging camera of FIG.1;

FIG. 3 is a schematic of the camera's IR sensor and the plurality ofsensing elements;

FIG. 4 is a flowchart of a method for capturing and displaying a thermalscene;

FIG. 5 is a flowchart of a method for processing captured IR data andpreparing the data for display;

FIG. 6 is a schematic illustration of the sensing element locations of asensor and a corresponding visual representation of a thermal scenecaptured by the sensor;

FIG. 7 is a flowchart of a method for determining and displayingtemperature rates of change between scenes;

FIG. 8 is a flowchart of a method for implementing the method of FIG. 7;

FIG. 9 is a flowchart of a method for determining and displayingtemperature rates of change for objects within a camera's field of view;

FIG. 10 is a flowchart of a method for implementing the method of FIG.9;

FIG. 11 is a schematic illustration of capturing an area of interest;

FIG. 12 is schematic illustration of determining a temperature rate ofchange for a given area of interest;

FIG. 13 is a flowchart of a method for determining and displayingspatial temperature rates of change between regions in a scene;

FIG. 14 is a flowchart of a method for implementing the method of FIG.13; and

FIG. 15 is a flowchart for a method for detecting and tracking areas ofinterest.

DETAILED DESCRIPTION

The following detailed description of the invention references theaccompanying drawings that illustrate specific embodiments in which theinvention can be practiced. The embodiments are intended to describeaspects of the invention in sufficient detail to enable those skilled inthe art to practice the invention. Other embodiments can be utilized andchanges can be made without departing from the scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment,” “an embodiment,” or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment,” “an embodiment,” or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso, not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the present technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Hardware

Embodiments of the present invention are directed to a thermal imagingcamera 100 comprising a generally rectangular housing 102; an opticalassembly 104 attached to a front face of the housing that focuses anddirects IR radiation into the housing; an IR sensor module locatedwithin the housing that senses intensities of IR radiation and thatfurther converts the radiation into electrical signals; a memory elementlocated within the housing that saves and records data, computerprograms, or other information; one or more processing elements locatedwithin the housing that performs data manipulations on the data; anelectronic display that presents visual representations of the data andthe data manipulations; and a user interface for customizing theoperation of the camera. Embodiments thus provide for the user of thepresent invention to sense IR radiation emitted from objects within thecamera's field of view and further to convert the sensed radiation intoa visual representation of the thermal scene. In addition, the cameramay obtain and display information indicative of the temperature rate ofchange of said objects within the thermal scene.

The housing 102 includes a generally rectangular base. The base may bemade from aluminum, acetal delrin, and/or combinations of similarmaterials that provide the base with high stiffness, low friction, anddimensional stability. In certain embodiments, the housing may containthe IR sensor, memory element, and processing element, each of which isdescribed in more detail below. The housing may also contain otherstandard circuitry components that may be required for operation of thecamera, such as printed circuit boards, integrated circuits,transistors, capacitors, inductors, or the like. A rear face of thehousing may contain an electrical connector assembly 202 that operatesto connect the camera to external display devices, power sources, andservo-motors. The connector assembly 202 may generally providecommunication between the camera's processing element and one or moreexternal components. The connector assembly 202 may include parallelports, serial ports, USB ports, IEEE 1394 high-speed serial bus ports,combinations thereof, and the like. The connector assembly 202 mayconnect to the external components through a wire or cable, opticalfiber, or wirelessly. An exemplary connector assembly may include aplurality of USB ports. The connector assembly may also couple to anetwork, such as the Internet, and may be able to communicateelectronically, through wires or cables, optically, through opticalfibers, wirelessly, using radio frequency (RF) protocols, such as IEEE802.11 standards, combinations thereof, and the like. The connectorassembly may additionally function to permit the camera to downloadcomputer programs or applications to be executed by the processingelement, as well as to upload data that is stored in the memory element.

The optical assembly 104 includes a generally cylindrical frame and anaperture formed through its longitudinal axis, wherein one or morefocusing lenses 106 may be positioned. The optical assembly 104 may alsoinclude a shutter assembly (not shown), which functions to open andclose the aperture, thereby allowing radiation to enter the camera. Theoptical assembly 104 may be made from aluminum or other suitablematerial that provides sufficient stiffness and dimensional stability.The focusing lens 106 may be made from any material suitable for IRoptical functions; however, in certain embodiments, the lens may becrafted from germanium. Because germanium is transparent to radiation inthe IR spectrum, it may be preferred for use in thermal applications. Inaddition, germanium has a high index of refraction, such that it may beuseful for wide-angle lens applications.

The IR sensor module is located within the base module and includes oneor more IR sensors 302. In certain embodiments, the IR sensor module mayinclude a focal plane array (FPA), thermopile, micro-cantilever, orbolometer. In additional embodiments, the sensor may be in the form ofan uncooled microbolometer, which includes a plurality of sensingelements arranged in a two-dimensional pixel array. Embodiments of thepresent invention provide for the array to be of any size. However incertain embodiments the array may be 160 pixels by 120 pixels, 320pixels by 240 pixels, or 640 pixels by 480 pixels. Each sensing element(i.e. 304, 306, 308, 310) detects the intensity of IR radiation incidentupon it. Each sensing element includes a bottom layer of siliconsubstrate with electrical contacts deposited thereon. The sensingelement also includes a top layer of IR absorbing material, such asamorphous silicon or vanadium oxide, which is spaced above the bottomlayer. Ends of the IR absorbing material are electrically connected tothe electrical contacts deposited on the bottom layer. Because the IRabsorbing material is spaced above the bottom layer, it is thermallyisolated from the other components of the camera. As IR radiation isabsorbed by the IR absorbing material, the material's electricalconductance measurably changes, with such changes being directlyproportional to the intensity of the IR radiation absorbed. Because,then, the intensity of IR radiation is proportional to the temperatureof the object emitting the radiation, the conductance change may becorrelated with the temperature of the object that emitted theradiation.

The memory element may include a computer-readable medium that mayinclude any device that can contain or store computer codes, programs,data, or applications for use by or in connection with the processingelement, discussed in more detail below. Examples of thecomputer-readable medium may include random-access memory (RAM), such asstatic RAM (SRAM) or dynamic RAM (DRAM), cache memory, read-only memory(ROM), flash memory, hard-disk drives, compact disc ROM (CDROM), digitalvideo disc (DVD), or Blu-Ray™, combinations thereof, and the like. Thememory element generally stores data to be utilized by the camera, suchas the measured IR radiation data. The stored data may also includecomputer codes, programs, applications, system settings, userpreferences, measured data, combinations thereof, and the like. Inaddition, the memory element may be configured to communicate with theprocessing element.

The processing element generally executes computer code, programs, orapplications and may include devices such as processors,microprocessors, microcontrollers, field programmable gate arrays(FPGAs), combinations thereof, and the like. The processing element mayfurther include clocks or timers. An exemplary processing element mayinclude the Blackfin® BF561 or BF608 processor from Analog Devices. Ineven further embodiments, the processing element may include two or moreprocessors, such that each processor is responsible for carrying-outseparate processes simultaneously. For instance, one processor may focuson rendering images, while the other is focused on performing datamanipulation. The processing element may utilize a computer operatingsystem, such as Windows® from Microsoft®, Inc. of Redmond, Wash. orLinux open source operating system. The processing element may beprogrammed using programming languages such as C#, .NET, and Flashprogramming. Thus, users of embodiments of the present invention maycustomize the performance of the present invention based on userpreferences. For example, the user may selectively adjust measurementparameters, such as field of view size, frame rate, temperature display,and color palettes.

The computer program of embodiments of the present invention thatdirects and controls the processing and memory elements may run directlyon the camera of embodiments of the present invention. Alternatively,the computer program may run on an external computing device, whereinthe computer program directs the processing element and memory elementlocated inside the camera via an electrical connection connected via theconnector assembly. In additional embodiments, the connection may bewireless. In even further embodiments, the processing and memoryelements may each be located on an external computing device. In such anembodiment, the computer program may direct the operation of theexternal processing and memory elements, such that that the camerafunctions to capture the thermal image data and to pass the data alongto the external processing and memory elements. In certain otherembodiments, the computer program may simultaneously run on the cameraand one or more external computing devices. Thus, a first portion of thecomputer program, code segments, or executable files may execute on thecamera, while a second portion of the program, code segments, orexecutable files may execute on the computing device.

The electronic display generally presents visual information, such as avisual representation of the thermal scene and any associated graphics,text, or combinations thereof to the user. The display may be configuredto communicate with the processing element. The display may include anymonitor or video device that utilizes technologies such as cathode raytube (CRT), plasma, liquid crystal display (LCD), light-emitting diode(LED), LED-LCD, combinations thereof, and the like. The display maypresent any screen shape and aspect ratio. In various embodiments, thedisplay may also include touchscreen capability, such that the user maytouch the screen to enter data, respond to prompts, display menus oradditional screens, and the like. The display may be in the form of anelectronic display that is embedded into an exterior side of thehousing. However, in additional embodiments, the display may be separatefrom the housing and connected to the processor via electronic cable orwireless connections.

The user interface generally allows the user to enter data into thesystem. The user interface may be configured to communicate with theprocessing element and may include devices such as keyboards, keypads,mice, tablets, pushbuttons, switches, knobs, dials, combinationsthereof, and the like. In some embodiments, the system may rely only onthe display with touchscreen capability for user input. In otherembodiments, the system may include the user interface in addition to,or instead of, the display with touchscreen capability.

Operation

Embodiments of the present invention are directed to thermal andinfrared imaging camera, computer program, and method that (1) displaythermal scenes; (2) determine temperature rates of change betweensuccessive thermal scenes, and (3) determining temperature rates ofchange between regions within a single thermal scene. Embodiments mayoperate by way of a method illustrated in FIG. 4. To display the thermalscenes, embodiments of the present invention employ the use of theprocessing element, the memory element, and/or any other combination ofcomponents that are controlled or directed by the computer program orthat are otherwise included in embodiments of the present invention.

The method of displaying the thermal scene includes Step 402 thatdirects, via the optical assembly, IR radiation into the camera and ontothe sensor; in Step 404, the sensor receives the IR radiation incidentupon the sensing elements via the optical assembly; in Step 406, thesensor is sampled to determine an intensity of IR radiation incidentupon the sensor and information obtained during the sampling isconverted into digital electrical data; in Step 408, the processingelement processes the electrical data to generate visual representationsof the temperature and to determine other temperature based information;and in Step, 410 the display presents the visual representations andother temperature based information for viewing by a user. In addition,the process may include Step 412, by which the user may manipulate thefunctions of Step 406 and Step 408, such that the user can adjustcamera, computer program, and method settings to function according tothe user's specifications.

By way of the Step 402, the lens of camera's optical assembly focusesradiation emitted from an object within the camera's field of view anddirects the radiation onto a single point, or sensing element, withinthe IR sensor. Thus, when considering the field of view as a whole, theoptical assembly focuses the entire thermal scene of the camera's fieldof view onto the sensor's plurality of sensing elements. The IRradiation incident upon the sensor's sensing elements is arepresentation of all the IR radiation being emitted from objects thatare 1) within the camera's field of view, and 2) emitting IR radiationdirected at the camera. Upon absorbing IR radiation, the conductance ofthe sensing elements changes in relation to the intensity of IRradiation being absorbed. In response, each sensing element emits anelectrical signal that is indicative of the conductance changeexperienced by the sensing elements. Thus, a visual representation, oran image, of the emitted IR radiation can be created by sampling theelectrical signals emitted from each sensing element of the sensor andconverting the electrical signals into visual representations of the IRradiation.

Once the optical assembly has directed the IR radiation into the camera,and onto the sensor, the electrical signals from the sensing elementsare sampled via the Step 406. Embodiments of the present inventionprovide for the sensing elements to be sampled at the frequency of theframe rate. The electrical signals generated by the sensing elements areconverted from an analog format to digital data before being processedvia the Step 408. Additionally, Step 406 may operate by way of acombination of hardware and computer program code segments that providelevel translation and data formatting, such that the digital data is informat that may be properly processed via Step 408. The sensing elementsampling may be performed in any order or along any direction in thetwo-dimensional array of sensing elements, such that a two-dimensionalvisual representation can be created. However, in certain embodimentsthe sensing elements are sampled in a sequential format such thatsubsequent sensing element sampling will be accurate representations ofreal-time thermal scenes within the camera's field of view. Forinstance, as illustrated in FIG. 3, the sampling of sensor 302 may startwith sensing elements 304 and proceed from left to right. Such samplingwould subsequently encounter sensing elements 306, 308, and each of thesensing elements in between. The sampling would continue advancing tothe right until the last sensing elements in the row has been sampled.Thereafter, the sampling begins on the second row of sensor 302,starting with sensing elements 310 and continuing across the second row.The sampling continues in such a manner until each sensing element inthe sensor 302 has been sampled. Embodiments of the present inventionthus provide for the continuous sensing and converting of the electricalsignals into digital data, such that visual representations of thethermal scene within the camera's field of view can be continuouslydisplayed in real-time.

In Step 408, the processing element is responsible for manipulating thedata received during Step 406 and for converting the digital data intohigh quality image and video representation of the thermal scene. Step408 may further comprise a method as illustrated in FIG. 5, whichincludes Step 502 that receives and stores the data from Step 406; aStep 504 that corrects the data for internal thermal measurement errors;a Step 506 that stores the data that was corrected in Step 504; a Step508 that assigns visual color representations to the data; a Step 510that stores the color assigned data from the Step 508; a Step 512 thatprepares the data for display; and a Step 514 that stores the databefore being displayed. In addition, Step 408 may include one or moretemperature rate of change methods, described in more detail below,which may manipulate the data to determine temperature rates of changefor objects, regions, or areas of interest within the camera's field ofview. The method steps illustrated by FIG. 5 may be implemented by theprocessing element, the memory element, or a combination of elementsthat are controlled or directed by the computer program of embodimentsof the present invention.

In embodiments of the present invention, the data obtained from samplingthe electrical signals of the sensing elements, via Step 406, may besaved in the memory element, via Step 502, before being processed orfurther manipulated. The data is saved in the memory element for eachframe cycle, such that data corresponding to each thermal scene obtainedby the camera is saved.

Step 408 may further include processes that improve and/or increase theaccuracy and precision of the data obtained from the sensing elements.For instance, Step 504 may determine the required offset and gain signaladjustments required to precisely correlate temperatures with thesignals obtained from the sensing elements. Some of the offset and gainadjustments may be due to internal characteristics and physicalstructures of the sensing elements. However, additional offset and gainadjustments may be required to correct for temperature variations thatoccur during normal use of the camera. In embodiments of the presentinvention in which the sensor is a microbolometer, because the IRabsorbing material is thermally isolated from the rest of the sensingelement, the sensor is generally thermally stable. However, there maystill be a window of stabilization that must be maintained via a loopcontrol. As an example, if the sensor is to be temperature stabilized at30 degrees Celsius with a tolerance of +/−0.25 degrees Celsius, then theloop control within the camera will adjust its output to maintain thespecified operating temperature parameters. In using these parameters,if the camera's noise-equivalent temperature at the sensor is 50 mK,then the processor may incorrectly detect a difference of 0.5 degreesCelsius when there may be no change in the IR radiation emitted fromobjects within the thermal scene. Thus, embodiments of the presentinvention provide for a lock-out or guard band function that preventsStep 504 from triggering on a sensed temperature drift, when such driftis within the noise-equivalent temperature. The tighter the loop controlmechanism, the more sensitive and accurate the processor becomes.

In embodiments of the present invention where a non-temperaturestabilized sensor is used, a two-point correction method, as is commonlyknown in the art, may be applied to the data before it is passed throughand saved in the memory element via Step 506. The two-point correctionmethod accounts for the temperature drift experienced duringnon-temperature stabilized operation. Such two-point correction methodmay incorporate the use of the camera's shutter assembly to determine abaseline sample reading from the sensor. When the shutter is closed,each sensing element in the sensor will be sensing the IR radiationemitted from the shutter. Because the shutter has a uniform temperatureand emits a uniform thermal scene, the processing element can determinethe expected baseline output from each sensing element, and by comparingthe expected readings to the baseline readings, the appropriate offsetand gain values for each sensing element may be determined. Thereafter,via Step 504, the data may be manipulated by incorporating the requiredoffsets or gain adjustments. Upon the data being corrected via Step 504,the error corrected data is stored in the memory element via Step 506.

By way of Step 508, the data stored in the memory element, via the Step506, is further manipulated by assigning visual color values for eachdata value that originates from a sensing element's electrical signal.In certain embodiments, the assigned color values include only grayscalecolors; however, in additional embodiments the full visual colorspectrum may be used. Because the electrical signal received from eachsensing element corresponds to the intensity of IR radiation sensed bythe sensing element, and because the intensity of IR radiationcorresponds to a temperature value, the color assigned to the datavalues that originated from the sensing elements likewise corresponds tothe temperature value. Thus, via Step 508, visual colors for eachsensing element are assigned, and a visual representation of the thermalscene can be created. For instance, sensing elements that indicate hightemperature data value may be assigned a lighter grayscale color such aslight grey or white. Whereas, sensing elements that return lowertemperature data value may be assigned a darker grayscale color such asdark grey or black. However, the choice of color scheme is arbitrary,and embodiments of the present invention contemplate the use of anycolor within the visual spectrum. As a non-limiting example, FIG. 6illustrates a visual representation 602 of the IR intensity emitted by ahuman face as captured by the sensor 302. In the visual representation602, the areas around the face's eyes 604 are displayed in white orlight grey, thus representing higher temperature values. Whereas, thearea around the face's nose 606 is displayed in dark grey or black,representing lower temperature values. Step 508 may additionally extractcertain key pieces of supplemental information, such as the minimum,maximum, and average scene temperature values. Such supplementalinformation may be displayed simultaneously with the visualrepresentation of the thermal scene.

In addition to the color assignment, Step 508 may optimize the contrastvalues of the data by using a histogram equalization function. In suchan embodiment, the histogram equalization function may sample each datavalue that originates from the sensor's sensing elements for a givenscene and determines a transformation function that linearizes the datavalues across all possible data values. Thus, Step 508 spreads out themost frequent data values, such that when the data values are assignedvisual colors, the areas of lower contrast may be given a highercontrast value, effectively increasing the clarity of the image.

Upon the data being assigned palette colors, the palette assigned datais stored in the memory element, via Step 510. Thereafter, the data isscaled to conform to standard image and video output parameters via Step512. Step 512 is responsible for converting the data to displaystandards that can be displayed via the electronic display. Such displaystandards may include, for instance, quarter-QVGA, QVGA, or VGA. Inaddition, Step 512 may be responsible for exporting the data tospecified video formats, such as NTSC or PAL. Once the data has beenconverted to the appropriate image or video display standard and format,the video data is stored in the memory element, via the Step 514 untilsuch time that it is displayed via the display in Step 410. Step 512 mayalso add the supplemental information (i.e. minimum, maximum, averagescene temperature values) into the video data, such that thesupplemental information can be displayed simultaneously with the visualrepresentations. Step 410 provides a visual output of the process imagedata received and manipulated by each step within the Step 408.

Additional embodiments of the present invention may provide for Step412, which includes a plurality of input controls that permits the usercustomize the operation of the camera. Such input controls may include,for instance, the ability changes the contrast and brightness levels ofthe display or to change the supplemental data that is displayed. Theuser may select the various inputs using the features embodiments of thepresent invention.

Temperature Rates of Change

The Operations section described above details a camera's method forconverting static or non-static IR based thermal scenes into a visuallydisplayable image or video. Embodiments of the present invention furtherprovide for methods to measure and display temperature rates of changefor objects within thermal scenes. In certain embodiments, the presentinvention provides for a camera, computer program, and method thatmeasure and display time based temperature rates of change for objects,regions, or areas of interest within the camera's field of view. Inadditional embodiments, the present invention provides a camera, method,and computer program to measure and display spatial based temperaturerates of change. Beginning with time based temperature rates of change;embodiments of the present invention permit such temperature rates ofchange to be determined for both static and non-static thermal scenes.Static scenes are defined as those scenes obtained by a stationarycamera with respect to stationary objects within the camera's field ofview.

As detailed below, for static scenes, the computer program ofembodiments of the present invention includes a plurality of codessegments executable by the processing element and memory element forperforming the steps of the method of the present invention. The stepsof the method may be performed in the order shown in FIG. 7, or they maybe performed in a different order. Furthermore, some steps may beperformed concurrently as opposed to sequentially. Also, some steps maybe optional.

The method includes the first step of capturing a first thermal imagescene with the thermal camera, Step 702. Via embodiments of the presentinvention, the temperature of each sensing element corresponding to theinitial thermal scene is calculated and stored in the memory element.Thereafter, a second thermal scene is captured with the thermal camera,Step 704. Via embodiments of the present invention, the temperature ofeach sensing element corresponding to the second thermal scene iscalculated and stored in the memory element. At Step 706, embodiments ofthe present invention compare the temperatures obtained from the sensingelements from the first and second thermal scenes and determine atemperature rate of change for each of the sensing elements betweenthermal scenes. The temperature rate of change is determined based on atime period over which the thermal scenes were captured. Finally, atStep 708, the temperature rate of change is displayed on the electronicdisplay of the present invention.

Steps for implementing the above-stated static scene temperature rate ofchange method are illustrated in FIG. 8 and include Step 802 that isresponsible for determining temperature rates of change for successivescenes that are stored in the memory element, via Step 506; in Step 804,the temperature rate of change determinations are refined and furthercalculations may be made to increased the accuracy of thedeterminations; and in Step 806, the temperature rate of change isfurther manipulated to generate a visual representation, which may thenbe overlaid onto the visual representation of the thermal scene storedin the memory element via Step 510. The steps illustrated by FIG. 8 maybe implemented by the processing element, the memory element, or acombination of elements that are controlled or directed by the computerprogram of embodiments of the present invention.

By way of Step 802, the corrected data saved in the memory element, viathe Step 506, is retrieved, and the temperature values originating fromeach sensing element for each thermal scene is determined. Upon adetermination of temperature value for successive scenes, Step 802further is responsible for determining the differences betweentemperature values for a given sensing element between successivescenes. Because all of the sensing elements in the sensor are employedto obtain temperature values for a given scene, Step 802 may determinethe differences between temperature values for all sensing elements inthe sensor. The result of the temperature difference determination for agiven sensing element is a time-based, temperature rate of change forthe sensing element. Once the rate of change determination has beenmade, the rate of change values corresponding to each sensing elementare stored in the memory element.

In additional embodiments of the present invention, the temperature rateof change may only be determined for a specified region of the thermalscene. In such an embodiment, groups of sensing elements comprising asubset of all of the sensor elements within the sensor are configured toreceive IR radiation from the regions. The user of the invention mayselect, via Step 412, regions in which to determine the temperature rateof change between successive scenes. In further embodiments, theprocessing element, via Step 408 may automatically select regions inwhich to determine temperature rates of change. In such an embodiment,the regions may be selected based upon the regions of having hightemperature values, or the regions may correlate to the group of sensingelements having indications of unique patterns or temperature profiles.

Step 802 may also include a temporal noise filter that operates toremove unwanted noise that may be introduced to each sensing elementbetween successive scenes. The temporal noise filter operates bycomparing the data from sequential sensing elements and estimating whichsensing elements were expected to change and which ones were not. Usingthe expectations, embodiment of the present invention can predict thosechanges that are the result of unwanted noise. As a result of thetemperature calculations and the noise filters, the magnitude of thechange in temperature between scenes can be represented by a graphicalmethod. Upon determining the temperature differences, such rate ofchange values may be saved in the memory.

By way of Step 804, the rates of change that are saved in the memoryelement are further manipulated by remapping the temperature rate ofchange vales to determine an even distribution across all vales. Suchprocess is functionally similar to the histogram equalization processthat was described above. Step 804 is responsible for sampling each rateof change value for each sensing element and determining atransformation function that linearizes the rate of change values acrossall possible values. Thus, Step 804 spreads out the most frequent rateof change values, such that of lower vale may be given a higher value,effectively increasing the clarity of the rate of change values.

Upon determining the rate of change values, Step 806 is responsible forassociating representative colors with each rate of change value andapplying the colors as an overlay to the thermal image data that issaved at the Step 510. The representation for the rate of change valuesmay include shades, or a range, of colors included in a gradient colorpalette. As an example, positive temperature rates of change (i.e. thoseassociated with heating) may be represented by the color red withsmaller magnitude rates of change may be identified using shades ofpink. Conversely, negative temperature rates of change (i.e. thoseassociated with cooling) may be represented by the color blue withsmaller magnitude rates of change identified using shades of light blue.In certain embodiments, as in FIG. 8, the colors may be overlaid ontothe thermal image data from Step 510. For example, the colors may bedisplayed simultaneously with the display of the thermal scene, such asbeing displayed simultaneously with visual representation 602. Sceneswithout any change may remain the original grayscale colors assigned byStep 508. In other embodiments, the colors representing the temperaturerate of change may be used exclusively as the visual representation ofthe scene. Because, temperature rate of change values, and correspondingcolors, are determined for each sensing element in the sensor, theresulting color representation is itself a visual representation of thetemperature rate of change of a scene. In such an embodiment, Step 508would not be employed, and Step 806 would provide the temperature rateof change data to the memory element, via Step 510. Thereafter, thedisplay of the present invention would display the visual representationof the temperature rate of change. In embodiments where only temperaturerates of change for regions of the sensor are being determined, Step 806may similarly overlay the rate of change representation onto the thermalimage data or the thermal change representation may be exclusivelydisplayed.

For non-static scenes, a temperature rate of change method, asillustrated in FIG. 9, may be employed. The method includes the firststep of capturing a first thermal image scene with the thermal camera,Step 902. Via embodiments of the present invention, the temperature ofobjects within the initial thermal scene are calculated and stored inthe memory element. At Step 904, areas of interest within the firstthermal scene are detected, wherein the areas of interest correspond topatterns representative of the arrangement of one or more of the objectswithin the thermal scene. The patterns and corresponding data are thusstored within the memory element. Thereafter, a second thermal scene iscaptured with the thermal camera, Step 906. Via embodiments of thepresent invention, the temperature of objects within the second thermalscene are calculated and stored in the memory element. The next stepincludes the detection of areas of interest within the second thermalscene and the storing of the pattern and corresponding data in thememory element, Step 908. At Step 910, embodiments of the presentinvention compare the areas of interest from the first and secondthermal scenes to determine if any of the areas of interest match. Ifmatching areas of interest are found, then embodiments provide for thedetermination of the temperature change between the areas of interest.Upon a temperature change determination, a temperature rate of change iscalculated, Step 912, wherein the rate of change is determined based ona time period over which the first and second thermal scenes werecaptured. Finally, at Step 914, the temperature rate of change isdisplayed on the electronic display of the present invention.

Steps for implementing the above-stated temperature rate of changemethod are illustrated in FIG. 10 and include Step 1002 that isresponsible for scanning the data received for each scene that is storedin the memory element, via Step 506, and detecting and matching areas ofinterest within the scene; in Step 1004, temperature rates of changethat occur between matching areas of interest in successive thermalscenes are determined; in Step 1006, for the temperature rate of changecalculations are refined and further calculations may be made toincreased the accuracy of the calculations; and in Step 1008, thetemperature rate of change is further manipulated to generate a visualrepresentation, which may then be overlaid onto the visualrepresentation of the thermal scene stored in the memory element viaStep 510. The steps illustrated by FIG. 10 may be implemented by theprocessing element, the memory element, or a combination of elementsthat are controlled or directed by the computer program of embodimentsof the present invention.

By way of Step 1002, the corrected data saved in the memory element, viathe Step 506, is retrieved and scanned to locate areas of interest.Areas of interest include patterns of data that represent objects orgroup of objects within the camera's field of view. Areas of interestmay include patterns that have an indication of high temperature valuesor patterns with indications of unique temperature profiles. Forinstance, as illustrated by FIG. 11, the pattern 602 representative of ahuman face may be scanned, and the areas around the face's right eye maybe determined to be an area of interest 1102. The area of interest 1102may have been selected because the pattern around the face's right eyehas a high temperature value. The areas of interest, including thepatterns and the corresponding data obtained from the sensing elements,are stored in memory for comparison with later scenes.

Via Step 1002, the data of the current scene is scanned to locate areasof interest. The scanning is performed periodically, with the timing ofthe scanning based on an interval timer. In certain embodiments, theinterval timer may correspond to the frame cycle. Upon the expiration ofthe timer, the data from the current scene is scanned to detect areas ofinterest. If an area of interest is detected, embodiments of the presentinvention attempt to match the area of interest with all other areas ofinterest previously found and stored in the memory element. The attemptsto match areas of interest are based on areas of interest having similarpattern shapes, similar temperature profiles, and/or similar velocity oracceleration profiles. If after scanning an entire scene a detected areaof interest does not match an area of interest stored in memory element,then the unmatched detected area of interest and its correspondingtemperature values are stored in the memory element for comparison withlater scenes. If a matching area of interest is found, the temperaturerate of change for the matched areas of interest is calculated via Step1004, as described below. Embodiments of the present invention providefor multiple areas of interest to be stored in the memory for comparisonand matching. Thus, embodiments of the present invention calculate thetemperature rates of change for areas of interest that are in motion orthat are in different spatial orientations between successive scenes.

For each detected area of interest, Step 1004 is responsible forcapturing the data and determining the temperature values originatingfrom each sensing element corresponding to the detected area ofinterest. The detected area of interest may simply comprise data from asingle sensing element; however, the area of interest may comprise datafrom a group of sensing elements. In certain embodiments, the step maydetermine the average temperature value for all of the sensing elementswithin the area of interest. By determining the average temperaturevalue, spatial noise inherent within a thermal scene may be averagedout. Further, because each data value originating from a sensing elementmay correspond to a pixel of a visual representation of the thermalscene, individual data values may hereafter be referred to “pixels.” Asan example, area of interest 1102 of FIG. 12 illustrates an area ofinterest that is 4 pixels wide by 6 pixels high.

After successive scenes have been sampled, and if areas of interest havebeen matched, Step 1004 is responsible for determining the differencesbetween the temperature values of matched areas of interest that weredetected in successive scenes. For instance, as illustrated in FIG. 12,area of interest 1102 is comprised of temperature data values obtainedfrom each sensing element that makes up area of interest 1102. The datacontained within temperature value pattern 1202 represents thetemperatures sensed by each sensing element during a first scene inwhich area of interest 1102 was detected. Next, the data containedwithin temperature value pattern 1204 represents the temperature sensedby each sensing element during a second scene in which area of interest1102 was detected. After obtaining temperature values for area ofinterest 1102 in at least two scenes, Step 1004 is responsible fordetermining the difference between the temperatures sensed by eachsensing element during the first and second scenes, and for storing theresults in the memory element. In the current example, differencepattern 1206 represents the temperature rate of change between each ofthe sensing elements corresponding to the area of interest 1102 detectedand matched during different scenes. Thus, the difference pattern 1206represents the magnitude of the temperature rate of change, asexperienced by the sensing elements comprising the area of interest1102. Specifically, pixel 1208B of pattern 1202 indicates a temperaturevalue of 31, which corresponds to a first temperature value from pixel1208A of area of interest 1102. Next, and corresponding to a secondscene, pixel 1208C indicates a temperature value of 32, whichcorresponds to a second temperature value from pixel 1208A of the areaof interest 1102. Via Step 1004, the rate of change between pixel 1208Cand pixel 1208B may be determined. It should be noted that for scenes inwhich the camera or area of interest are stationary, pixels 1208B and1208C will likely correspond to the same sensing element. However, fornon-static scenes, areas of interest may change spatial orientations,such that although the spatial pattern of the area of interest remainsthe same, the sensing element corresponding to a particular portion ofthe area of interest will likely change. Returning then to the presentexample, as illustrated by pixel 1008D of rate of change pattern 1206,the temperature rate of change experienced is +1, corresponding to anincrease in temperature. Similarly all temperature rates of changedisplayed in rate of change pattern 1206 represent the rate at whicheach sensing element comprising area of interest 1102 changes intemperature over time.

Step 1004 may also include a temporal noise filter that operates toremove unwanted noise that may be introduced to each area of interestbetween successive scenes. The temporal noise filter operates bycomparing the data from sequential areas of interest and estimatingwhich sensing elements were expected to change and which ones were not.Using the expectations, embodiment of the present invention can predictthose changes that are the result of unwanted noise. As a result of thetemperature calculations and the noise filters, the magnitude of thechange in temperature between successively captured regions of interestcan be represented by a graphical method. Upon determining thetemperature differences, such rate of change values are saved in thememory.

By way of Step 1006, the rates of change that are saved in the memoryelement are further manipulated by remapping the temperature rate ofchange vales to determine an even distribution across all vales. Suchprocess is functionally similar to the histogram equalization processthat was described earlier. Step 1006 is responsible for sampling eachrate of change value for each area of interest and determines atransformation function that linearizes the rate of change values acrossall possible values. Thus, Step 1006 spreads out the most frequent rateof change values, such that the areas of lower vale are given a highervalue, effectively increasing the clarity of the rate of change values.

Upon determining the rate of change values, Step 1008 is responsible forassociating representative colors or graphics with each rate of changevalue and applies the graphics to the thermal image data that is savedat the Intermediate Image Step 510. The representation for the rate ofchange values may include graphics or a gradient color palette. As anexample, positive temperature rates of change (i.e. those associatedwith heating) may be represented by the color red with smaller magnituderates of change may be identified using shades of pink. Conversely,negative temperature rates of change (i.e. those associated withcooling) may be represented by the color blue with smaller magnituderates of change identified using shades of light blue. For instance, asillustrated in FIG. 12, the rate of change indicated by pixel 1208D ofthe temperature rate of change pattern 1206 is +1, which indicates apositive rate of change. Thus, a light shade of pink may be overlaidonto the corresponding portion of the area of interest 1102 anddisplayed simultaneously with visual representation 602. Similarly, therate of change indicated by element 1210D of rate of change pattern 1206is −2, which indicates a negative rate of change. Thus, a light shade ofblue may be overlaid onto the corresponding area of interest 1102 anddisplayed simultaneously with visual representation 602. Samples withoutany change may remain the original grayscale colors assigned by Step508. In other embodiments, the colors representing the temperature rateof change may be used exclusively as the visual representation of thescene because, temperature rate of change values, and correspondingcolors, are themselves a visual representation of the temperature rateof change of a scene. In such an embodiment, Step 508 would not beemployed, and Step 1008 would provide the temperature rate of changedata to the memory element, via Step 510. Thereafter, the display of thepresent invention would display the visual representation of thetemperature rate of change.

The above-described methods may be implemented when determiningtemperature rates of change over time. However, for temperature rates ofchange that may be occurring during a single moment in time, embodimentsof the present invention provide for a camera, computer program, andmethod that determine and display spatial temperature rates of change.For instance, embodiments of the present invention may determine anddisplay a magnitude and direction of temperature change within a singlescene. Such magnitude and direction may be referred to as a heat flow.As detailed below, the computer program of embodiments of the presentinvention includes a plurality of codes segments executable by theprocessing element and memory element for performing the steps of themethod of the present invention. The steps of the method may beperformed in the order shown in FIG. 13, or they may be performed in adifferent order. Furthermore, some steps may be performed concurrentlyas opposed to sequentially. Also, some steps may be optional.

The method includes the first step, Step 1302, of selecting two or moreregions within the camera's field of view. Subsequently, via step 1304,a thermal image scene is obtained with the thermal camera. Embodimentsof the present invention then provide for the temperature obtained fromeach sensing element that corresponds to each of the regions to becalculated and stored in the memory element. Thereafter, at Step 1306,embodiments of the present invention compare the temperatures obtainedfrom the sensing elements corresponding to the two or more regions anddetermine a temperature rate of change between each of the regions. Thetemperature rate of change is determined based on a magnitude and adirection in which the temperature difference occurred. Finally, at Step1308, the temperature rate of change is displayed on the electronicdisplay of the present invention.

Steps for implementing the above-stated temperature rate of changemethod are illustrated in FIG. 14 and include Step 1402 in which two ormore regions are selected from a thermal image scene that was stored inthe memory element, via Step 506; in Step 1404, a temperature rate ofchange determination is made between the regions; and in Step 1406, thetemperature rate of change is further manipulated to generate a visualrepresentation, which may then be overlaid onto the visualrepresentation of the thermal scene stored in the memory element viaStep 510. The steps illustrated by FIG. 14 may be implemented by theprocessing element, the memory element, or a combination of elementsthat are controlled or directed by the computer program of embodimentsof the present invention.

By way of Step 1402, two or more regions may be selected from thecorrected data saved in the memory element, via Step 506. In certainembodiments of the present invention, the user of the invention mayselect, via Step 412, regions. In further embodiments, the processingelement, via Step 408 may instead select the regions. In such anembodiment, the regions may be selected based upon the regions of havinghigh temperature values, or the regions may correlate to groups ofsensing elements with indications of unique patterns or temperatureprofiles. After the regions have been selected, embodiments of thepresent invention determine, via step 1404, temperature values for theregions. In certain embodiments, the process element may determine anaverage temperature vale for all of the sensing elements, or group ofsensing elements, that correspond to a region. Such averaging isadvantageous because it may average out any erroneous or incorrecttemperature measurements that may be inherent in the sensor.

Upon a determination of temperature values for the two or more regions,Step 1404 is responsible for determining the differences betweentemperature values for the regions. Via Step 1404, the processingelement determines the difference between the average temperature valuesof the two or more regions. Such a determination results in both amagnitude of the temperature difference and a direction that existsbetween the two regions. As a result, the temperature differencedetermination for two given regions within a scene may be referred to asa thermal vector. Once the rate of change determination has been made,the rate of change values corresponding to each region are stored in thememory element.

Upon determining the rate of change values, Step 1406 is responsible forassociating representative graphics with each rate of change value andapplying the graphics as an overlay to the thermal image data that issaved in the memory element, at the Step 510. The representation for therate of change values may include graphics in an arrow shape, thusrepresenting a vector. The direction of in which an arrow is positionedand overlaid onto the thermal image may be in the existing directionthat spatially separates the two or more regions. In addition, themagnitude of the temperature rate of change may be displayed via thearrow, as either a particular color, length, or size of the arrow. As anexample, positive temperature rates of change (i.e. those associatedwith heating) may be represented by the color red with smaller magnituderates of change may be identified using shades of pink. Conversely,negative temperature rates of change (i.e. those associated withcooling) may be represented by the color blue with smaller magnituderates of change identified using shades of light blue. In suchembodiments, the color of the arrow is representative of the magnitudeof the temperature rate of change. In additional embodiments, the sizeor length of the arrow may be indicative of the magnitude of temperaturerate of change. In such an embodiment, a smaller or shorter arrow wouldbe indicative of a relatively small temperature rate of change, whereasa larger or longer arrow may be indicative of a relatively largetemperature rate of change. In certain embodiments the graphics may beoverlaid onto the thermal image data from Step 510. For example, thearrows may be displayed simultaneously with the display of the thermalscene, such as being displayed simultaneously with visual representation602. Scenes without any change may remain the original grayscale colorsassigned by Step 508. In other embodiments, the graphics representingthe temperature rate of change may be used exclusively as the visualrepresentation of the scene. In additional embodiments, a numericalfigure may be presented on the display to represent the magnitude of thetemperature rate of change.

Detection and Tracking

Embodiments of the present invention further provide for the detectionand tracking of objects within the camera's field of view. In such anembodiment the camera works in conjunction with two or more servo-motorsthat operate to rotate the camera in both pan and tilt directions, suchthat the camera may rotate to cover all directions. The camera may workwith any type of general, off-the-shelf servo-motor, but in certainembodiments two HS-985MG SERVO servo-motors may be used. Suchservo-motors are capable of handling payloads of up to two pounds. Theservo-motors are controlled by independent servo-motor drivers, such asthe Polulu Servo Driver. The servo-motor driver provides the interfacebetween the camera and the motors. The camera instructs the driver onhow to control the servo-motors, such that the camera is continuallydirected at areas of interest that are to be tracked.

An embodiment of the detection and tracking method is illustrated inFIG. 15 and broadly includes Step 1502 that analyzes and detects areasof interest; a Step 1504 estimates the current and future locations ofthe detected areas of interest; and a Step 1506 that communicates withthe driver and servo-motors to guide the camera. In Step 1502, areas ofinterest detected in Step 1002 are analyzed. Areas of interest thatexceed specified temperatures, or other consideration thresholds, areconsidered targets and are saved in the memory for further processing.The position, pattern, and temperature readings of the targets are allsaved for processing. After all targets have been detected in a givenscenes, Step 1502 analyzes all targets and selects the most significanttarget that is likely to pose the largest threat. The threat level of atarget may be dependent on factors such as temperature level or the sizeof the target. The target that is determined to be the largest threat ispassed on for tracking, via Step 1504.

By way of Step 1504, the targets are tracked in either a linear ornon-linear tracking mode. The linear tracking mode functions bydetermining the displacement between the sensor's center sensing elementand the position of the target for every frame cycle. Step 1504 providesinstructions to be performed via the Step 1506, which directs theservo-motors to rotate the camera to a position where the target ispositioned at the camera's center sensing element. Because the Step 1504determines the displacement between the center sensing element and thetarget for every frame cycle, the servo-motors update the position ofthe camera at essentially the same rate as the frame cycle.

In the non-linear tracking mode, Step 1504 is responsible for trackingthe motion of the target and estimating where in the camera's field ofview the target is likely to be in the future. In such an embodiment,the Step 1504 obtains the temperature rates of change data from thetemperature rate of change method described above. In Step 1504, thetemperature values for the sensing elements are monitored in sequentialscenes. Positive rates of change represent a target's current position,and negative rates of change represent the target's previous position.To determine a displacement, the absolute maximum values for thepositive and negative rates of change for a selected target isdetermined. Because this maximum value coincides to the region of thetarget that carries the most thermal energy, it is generally immune toaspects of the target that may trigger false rate of change values orother errors. The displacement between maximum positive and negativevalues is compared to displacements measured in previous frame cycles todetermine the target velocity and acceleration. The velocity of thetarget is measured in sensing elements per second, whereas theacceleration is measured in sensing elements per second squared. Step1504 may then estimate what the expected position will be based on thecurrent velocity and predicted acceleration. Instructions are thenprovided to and are carried out via the Step 1506, which direct theservo-motors to rotate the camera to a position where the target ispositioned in the center of camera's field of view. In some instances,there may be tracking errors that are generated due to servo-motorposition errors and servo-motor step sizes that are not in line with thepredicted displacement of the target. Such errors are manifested asrounding errors. To combat such rounding errors, embodiments of thepresent invention provide for Step 1504 to sub-sample the sensingelements that are immediately outside the sensing elements that areincluded in the target. Such sub-sampling serves to trim out any errors.In such an embodiment, the estimation protocols from Step 1504 permitthe camera to command the servo motors to guide the camera quicker andmore efficiently than in the linear mode.

Once the target is being tracked via the Step 1504, commands are sent,via Step 1506 to the servo-motor's driver 1108 to instruct the motors1510 and 1512 on how to position the camera such that the target islocated in the center of the camera's field of view.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims. Forexample, other alternative embodiments may combine various inventivefeatures described above. As a non-limiting example, variations onmethods for displaying temperature rates of change may be used. Inaddition, the detection and tracking method may additionally integrateand combine various aspects of the temperature rate of change methods,such that the present invention includes determining and displayingtemperature rates of change along with tracking targets.

Having thus described various embodiments of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:
 1. One or more non-transitory computer-readable mediastoring computer-executable instructions that, when executed by aprocessor, is operable to measure temperature rates of change of aregion within a field of view of a thermal imaging camera according tothe following: detect, via at least one infrared radiation sensorassociated with the thermal imaging camera, an intensity of thermalradiation incident upon said sensor during one or more thermal scenes;store, in a memory element associated with the thermal imaging camera,data comprising the intensity level of thermal radiation incident uponthe sensor during the one or more thermal scenes; automaticallymanipulate the data to determine continuously updated temperature ratesof change of said region within the camera's field of view and generatecontinuously updated video representations of the temperature rates ofchange of said region, wherein the rates of change are determined bycomparing the data detected by the sensor between at least two of theone or more thermal scenes; and present, in real time and on a displayassociated with the thermal imaging camera, the continuously updatedvideo representations of the temperature rates of change of said region.2. The computer-readable media of claim 1, further operable to present,on the display, a magnitude of the temperature rate of change as agraphic color display, with negative temperature rates of changedisplayed in shades of a first color and positive temperature rates ofchange displayed in shades of a second color.
 3. The computer-readablemedia of claim 1, wherein the region corresponds to a single objectpresent in the field of view.
 4. The computer-readable media of claim 3,further operable to track motion of the object within the field of view.5. The computer-readable media of claim 1, further operable to performone or more of the following: temperature drift correction, patternrecognition, spatial noise filtering, and temporal noise filtering. 6.The computer-readable media of claim 1, further operable to present, onthe display, at least one of the following: minimum, maximum, andaverage temperatures of the region.
 7. The computer-readable media ofclaim 1, further operable to: automatically manipulate the data todetermine continuously updated temperature rates of change of a secondregion within the camera's field of view and generate continuouslyupdated video representations of the temperature rates of change of saidsecond region; and present, in real time and on the display, thecontinuously updated video representations of the temperature rates ofchange of said second region.